add cast to avoid compiler warning
add cast to avoid compiler warning

git-svn-id: 6df6fa3ddd728f578ea1442598151d5900a6ed44@327 630680e5-0e50-0410-840e-4b1c322b438d

da2ce7/protobuf,kastnerkyle/protobuf-py3,spilgames/protobuf,chandlerc/protobuf-llvm,mkrautz/external-protobuf,machinalis/protobuf-python3,mpapierski/protobuf,lcy03406/protobuf,GreatFruitOmsk/protobuf-py3,patrickhartling/protobuf,beyang/protobuf,aidansteele/protobuf-mirror,GreatFruitOmsk/protobuf-py3,aidansteele/protobuf-mirror,mikelikespie/protobuf,mikelikespie/protobuf,svn2github/google-protobuf,Distrotech/protobuf,spilgames/protobuf,spilgames/protobuf,kastnerkyle/protobuf-py3,machinalis/protobuf-python3,da2ce7/protobuf,mpapierski/protobuf,lcy03406/protobuf,GreatFruitOmsk/protobuf-py3,chandlerc/protobuf-llvm,svn2github/protobuf-mirror,machinalis/protobuf-python3,lcy03406/protobuf,mikelikespie/protobuf,GreatFruitOmsk/protobuf-py3,datacratic/protobuf,Distrotech/protobuf,svn2github/protobuf-mirror,svn2github/google-protobuf,mkrautz/external-protobuf,mkrautz/external-protobuf,beyang/protobuf,svn2github/google-protobuf,patrickhartling/protobuf,da2ce7/protobuf,kastnerkyle/protobuf-py3,datacratic/protobuf,datacratic/protobuf,patrickhartling/protobuf,mkrautz/external-protobuf,svn2github/google-protobuf,spilgames/protobuf,svn2github/protobuf-mirror,chandlerc/protobuf-llvm,spilgames/protobuf,aidansteele/protobuf-mirror,aidansteele/protobuf-mirror,svn2github/protobuf-mirror,aidansteele/protobuf-mirror,patrickhartling/protobuf,mpapierski/protobuf,beyang/protobuf,datacratic/protobuf,lcy03406/protobuf,mikelikespie/protobuf,beyang/protobuf,GreatFruitOmsk/protobuf-py3,lcy03406/protobuf,mikelikespie/protobuf,svn2github/protobuf-mirror,mpapierski/protobuf,mpapierski/protobuf,Distrotech/protobuf,datacratic/protobuf,da2ce7/protobuf,kastnerkyle/protobuf-py3,chandlerc/protobuf-llvm,Distrotech/protobuf,kastnerkyle/protobuf-py3,Distrotech/protobuf,beyang/protobuf,chandlerc/protobuf-llvm,machinalis/protobuf-python3,mkrautz/external-protobuf,patrickhartling/protobuf,svn2github/google-protobuf,da2ce7/protobuf